The invention relates to filter assemblies, e.g., those used to filter aviation fuel.
Filters used to remove impurities from aviation fuel and to cause water in the fuel to coalesce into large drops that can settle and be removed by a sump pump are often sealably mounted over inlet openings in the bottom or side walls of fuel tanks or pressurized vessels through which the fuel flows immediately prior to discharge, such that liquid must pass through the filter before it enters the tank or vessel. These filters are often cylindrical and have an axial opening at the bottom and a tubular filter medium wall through which there is so-called inside-out flow. Similarly shaped filters can be mounted over outlets, in which case there would be outside-in flow.
These cylindrical filters have typically been secured by mating a threaded lower end of a filter cartridge base with a threaded opening in the floor of the tank or vessel or by sliding the filter over a floor-mounted threaded rod and holding it in place with a nut at the top of the filter. If the filters are overtightened, the threads may become worn, and the filters hard to remove. If the filters are undertightened, the filter may not seal well and may even be loosened by vibrations.